ZOLL M2 Operator's Manual page 95

A continuous tone sounds for 10 to 50 seconds (depending on configuration), followed by a
higher pitch tone for 5 to 10 seconds. If the shock is not delivered within this 15 or 60 second
interval (depending on configuration), the defibrillator disarms itself and begins a CPR period.
See "3 Press SHOCK" on page 8-8 for the next steps to follow.
No Shock Advised When a nonshockable rhythm is detected, the unit displays a NO
SHOCK ADVISED message. After this message, immediately begin chest compressions and
continue other treatments per protocol.
9650-000860-01 Rev.C ZOLL M2 Operator's Guide 8-7